121778149 has 8 divisors (see below), whose sum is σ = 123116760. Its totient is φ = 120446976.

The previous prime is 121778119. The next prime is 121778171. The reversal of 121778149 is 941877121.

It can be written as a sum of positive squares in 4 ways, for example, as 624100 + 121154049 = 790^2 + 11007^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 121778149 - 2⁵ = 121778117 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (121778119) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 34917 + ... + 38245.

It is an arithmetic number, because the mean of its divisors is an integer number (15389595).

Almost surely, 2^121778149 is an apocalyptic number.

It is an amenable number.

121778149 is a deficient number, since it is larger than the sum of its proper divisors (1338611).

121778149 is a wasteful number, since it uses less digits than its factorization.

121778149 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3719.

The product of its digits is 28224, while the sum is 40.

The square root of 121778149 is about 11035.3137245844. The cubic root of 121778149 is about 495.6667530965. Note that the first 3 decimals are identical.

The spelling of 121778149 in words is "one hundred twenty-one million, seven hundred seventy-eight thousand, one hundred forty-nine".